Machine and method for forming and welding hollow glass blocks



W. S. MAYERS MACHINE AND METHOD FOR FORMING AND WELDING HOLLOW GLASS BLOCKS Filed Sept. 3, 1937 8 Sheets-Sheet l March 9, 1943.

l PAA/16oA 's Sheng-sheet 2 I/AvlllNfl w. s. MAYERs MACHINE AND METHOD FOR FORMING AND wELDINGHoLLow GLASS BLOCKS Fileasept. s, les? .F/E. E

F! G. EL

Marh 9, 1943.

March 9, 1942..` w. s. MAYERS MACHINE ANDAMETHOD FOR FORMlNG AND WELDING HOLLOW GLASS BLOCKS Filed Sept. "5,l 1957 8 Sheets-Sheet 3 Marth 9, 1943. w, 5 MAYERS l 2,313,160

MACHINE AND METHOD FOR FORMING AND WELDING HOLLOW GLASS BLOCKS Filed Sept. 5, 1937 8 Sheets-Sheet 4 R/amh w95, 1943!, w. s. MAYERS CHINE AND METHOD FOR FORMING AND WELDING HOLL-OW GLASS BLOCKS 8 Sheets-Sheet 5 Fild Sept. 3, 1937 F/G V1D,

/NVENTUR w. s. MAYERs 2,313,160

MACHINE AND METHOD FOR FORMING AND WELDING HOLLOW GLASS BLOCKS March 9,

' a sheets-shea V6 Filed Sept. 5, 1957 IINVEIVTUR @MW MACHINE AND METHOD FOR FORMING AND WELDING HOLLOW GLAss BLOCKS March 9, 1943. w. s. MAYERS Filed Sept. 3, 1937 8 Sheets-Sheet '7 INVENTUR Mgg-ch 9, 1943;. wf` s'. MAYERS d 2,313,160

1 MACHINE AND MTHD-FOR FORMING AN WELDING HOLLOW GLASS BLOCKS YFi1d"septs, 1957 8 snags-sheet s /NVEN TUR @WwW/469,.,

Patented Mar. 9, i943 MACHINE AND METHOD FOR FRG "i i WELDING HOLLOW GLASS BLOCKS Wilbur s. Meyers, roles, om

Application September 3, 1937, Seriai No. 162,237

16 Claims. (Cl. 49-1) This invention relates to machines for pressing articles from globules or gobs of molten glass f stationary, coincide with horizontal planes, those which are deposited in molds in regular successhaped components, thus forming hollow blockswhich may be rectangular in shape or in other desired forms.

Up to the present time, these half blocks have been molded and then joined together in subsef quent operations by'various methods involving at the sides coincide with vertical planes, all parallel with the axes of the rotating carriers.

' In operation, while the' two molds at the tops' of their carriers, which at thatI moment are at rest, are receiving their chargespf molten glass in which these are pressed into form, the rims of the adjacent molds registering with one another are, by means hereinafter described, caused to move toward one another until theyV are in contact under pressure, at which time the plastic rims n rmly cohere causing perfect welding ben tween the halves to take place. In a short in- 'f tervai of time the sheusof the moms are caused a considerable amount of hand work which necessarily limits the speed of production and adds to the manufacturing costs.v Furthermore, the blocks so made and joined most often do not register perfectly at the junction of the two parts to recede to their former positions but, by described means, the now welded block' is held stationary during the recession of the. mold shelfs from'whichit is then free, and finally the block which is a distinct disadvantage when building l;

them into walls.

' The object of my invention is to provide methods and means for doing away with all hand work in joining the halves of the blocks and to attain practically perfect registry at their junction with one another, the blocks being delivered by the v machine as a finished product and after being annealed they are ready for the market.

To accomplish this result, I employ co-acting twin pressing machines which, contrary to the established custom, contain mold carriers which are supported wholly by and rotate upon horizontal shafts, the two pressing machines beingin working relation and in directional opposition, one to the other. The mold carriers are actuated simultaneously and may be identical in their component'parts, the rotation and welding parts of one, however, being in the opposite direction from the other.

The supply of the molten glass mold charges at timed intervals requires either two feeders of any well known type, set with right and left deliveries opposite the ends of the machine base or a single feeder with double orifice and delivery set on the centerline between the machine pair,

the mold charges in either case being delivered simultaneously and deiiected by adequate chutes, or by other means'to the molds. In thisl construction there are four molds in each carrier, each placed with their centers upon radial lines 90 degrees from one another andupon-common radial planes. Thus while the edges of the molds 40 their plasticity so that they do not collapse due holdingmeans also recede a short distance allowing itto drop by gravity upon a vertically reciprocating plate from which itis delivered to `fa Jchute member and then sliding by gravity to a take-away conveyor, all the above operations taking place at the same time and during a rest period of the intermittently rotated carriers.

As ,the adjacent molds in their welding posif tions' are in perfect register and asthe Welding is donewhilethe halves are stillwithin their respective molds, itis obvlous'thatlthe finished blocks must emerge from their molds in perfect register and without distortion. y

'As the mechanical and structural members of the twin mold carriers are identical, one with 'I the other, the distinctions between them residing inthe opposed directions oi certain moving parts,

-a description of one will apply to the other.

As the blocks become cooled by radiation their 'sealed-in air contents contract thus causing partial vacuums therein. As these vacuums build up, the walls of the blocks are gradually losing l to atmospheric, pressure, all pressed glassware, therouter surfaces are/chilled by contact with the muchfcolder mold walls, forming temporarily rigid `jackets around their molten interiors which is an important factor in the prevention of distortion. The degree of chilli/ng the glass surfaces may be regulated byadiusting the iiow of the mold cooling mediumthrough means herein described.' In cases where vit is ydesired that the blocks should have exceptionally thin walls, insurance against possible distortion byA atmospheric pressure is provided by-means here inafter disclosed.

" at the tops and bottoms of the carriers, while 5o With reference to the, drawingsfFi/g. 1` is a f/ bolted rigidly to the frames.

front elevation showing thetwin pressing and molding machines mounted upon their common base and joined by a top connectingmember; Fig. 2 is an end elevation showing the right hand pressing and molding machine; Fig'. 3 is a combined plan and horizontal section of the right hand machine, the part section being taken on the axis of the mold carrier; Fig. 4 is an elevation of the right hand mold carrier with a fragmenr tary portion sectionalized upon the radial center coupling; Fig. l1 is a horizontal centerplane section through an automatic hold-down of a pneuf` matic distributing disk; Fig. 12 is a transverse part elevation showing the finished block lowering device; Fig. 13 is a part front elevation show-i ing the lowering device; Figures 14 and 15 show' radial `lcenterpl'ane.sections of a mold in two stages of the welding cycle; Figuresl and l1'? show sectionsof curved face block` halves before and after welding; Figures 118 and 19 show sections of straight face block` halves before and after welding; Figures 20, 21, and 22 show sections of curved face blocks in which the welding planes are at midwaypoints and pass through the curved faces at right angles thereto.

The structural member of the twin machine comprises the common base I. the frames 2R, 2L, and the top connecting member 3. The frame bases are doweled and securely bolted to the base and the ends of the top connecting member are In the frames, and integral parts thereof, are the housings for the driven shafts and cooling medium collectors here-` inafter described.

The drive shaft 4' isfjiumald ni the bearings 45 5, 6 and keyed to the wormsxl, it being understood that the same numerical -reference character applies to like parts in both the right and left hand machines.

The spur gear 8 vmay be keyed to either end of the drive shaft and isdriven through suitable intermediate gearing by 'a motor, not shown. On

the drive shaft at the ends of the worms are the,l ball or roller thrust bearings 9. The drive .shaft ADuring the dweil periods the upper moldsoxi is in two piecesof equal length which are keyed to their respective halves of the coupling I0.

The contacting rims of the coupling halves have i VV small radial grooves, as shown in Fig. \3., each registering with the other, providing circumferential adjustment in small angles sothat when clamped together by the bolts II non-slippage is secured. The coupling flanges are slotted.as in Fig. 10, for the bolts II so that this iangular adjustment may be made.

The set screws I2 are for the purpose of -separating the halves,v sliding one or the other on its shaft, when such adjustment is to be made.

The worms, in right andleft hand pair, mesh with' the worm gears I3 which are thus driven in opposite rotative directions. .The worm gears, the

roller arms I4, roller disks I- and cams IB are each keyedto the intermediate shafts I1 and `these shafts are journaled in the bearings I3,

I9, 20, preferably of the roller type.

For driving the mold carriers 2I in intermittent stages the well known Geneva gears 22 are employed, each having four teeth, as shown.

It willbe observed that for each rotation of the intermediate shafts the Geneva gears make a 5 quarter turn and that their dwell period is three fourths of the time in which the intermediate shafts make one rotation. In order to secure ample strength of the parts' the gear driving rollers 23 are journaled on the pins 24 which are l0 tightly tted at both ends between and into the double arms I4.

After becoming worn to a more or less extent, the Geneva gears may not, due to lost motion, place the opposed molds in the welding position 15 in precise register, nor the top molds in accurate line with the plungers. Toguard against this condition, there are provided the wedge shape stops 25. These stops are preferably of hardened steel and have integrally extended-Shanks which are riveted to the rocker arms 25. These rocker arms are fulcrumed on the bushings 21 which have a slight eccentricity'on their shafts 28. Extending upwardly from the bearings 29 are two lugs 29-a and between them are the short arms Z'I-a which are integral with the uushings b1. Vrrn@ screws so are threaded into il'the" lugs 29'a and engage the eccentric arms 2.1-a.. By adjusting these screws the eccentrics may be rotated a limited amount of their '30, shafts thus increasing or diminishing .the distance between the shaft centers andthe stops 2li, affording great precision of adustmeri AThe stops, when raised by thefcams IS, en rthe notches 2I-a in close contact therewith so that there is no lost motion between these pt irts. The

cams I6 are pinned upon the shafts I'Ilin working relation to the other members mounted upon the shafts in such manner that the locking-f. arms are raised and lowered only durlngifthe `',dv'egell 40 periods of the Geneva gears. j n., for?.

'Ihe mold carriers are mounted upon-'and keyed to their shafts 3l, these shafts beingiournaled,

preferably withfroller bearings 32tt'd `(infhousings in the frames 2R, 2L. Theselishaftsare distance between the adjacent mold edges is a' ypredetermined amount greate'rti'an the thickness i of the glass blocks to be manufactured. By the provision of certain featuresandvthe Amodiilca- `tion of others this distance may be'made variable 5o without affecting thedncthd Vof operation. The mold housings may be made separable' from their carriers so that different forms anlsizes lmay be v-,used without affecting the method..`

Pressing operation 1 both carriers are in positions tto.- receive their charges of molten glass which arejformed andI V-v'-`I, air pressure is admitted;throughfthe'pir'iesV 34 immediately after the moldsj have sir' r`i,ul,tane` ously received their charges. This actiontcauses both pistons 36 and plungers 31, to descend into their molds with adequate force by jwhich the half blocks are pressed into form. Remaining in the molds for a predetermined length of time for cooling the glass the cam T--I now reverses the valve V--I admitting air pressure in the pipes 35 with exhaust in the pipes 34, thus causing the piungers to rise clear of the molds.

For the purpose of maintaining accurate align- In the lower naif of their'c'ircuis pei rollers, engage the semi-circular guidesl in rolling contact by which means the mold parts and the eiectors and bottoms forming the bottoms 1;. In this cievice the secondary cylinders C-z and pistons P2 are omitted and are replaced by the ratchet members |09, pawl members H0, release y guides 39 xed to the machine frames. The mold caps 40 have box-like upward extensions machined to an easy i'lt over the plunger bodies so 5 that the caps will remain in alignment. The cap springs 4I cause the caps to be seated a short time before the plungers reach their lowest points.

A cooling medium, preferably water, enters the hollow plunger interiors through the inlet pipes 42, and passes out through the outlet pipes 43, all having rubber hose connections with a supply pipe, not shown.

It is obvious that the timing of both plungers as well as the mold parts may be done by either of thecombinations shown in Fig. 1 o'r the two may be placed in synchronism with independent operations and connections. The timer shafts 33 are shown as beingdriven by chains 44 on sprocket wheels 45, 46 having one to one ratios, this arrangement economizing space. Air pressure is admitted to the valve V-I through its lower pipe connection. Fig. 8 shows a preferred type of balanced valve with spring return but anytype of 3way valvev and closed or box cam may be substituted without affecting the operation.

For the purpose oi preventing thesliding members of the molds from dropping to their outward positions by gravity during theirwtravel below the 30 horizontal center lines of the carieragthere are tted to each mold shell the studs upon which! are journaled the rollers 58.1; i f

,- these are held from sliding outwardly in their housings.

Welding operation N During each of the above described dwell periods and coincident with the pressing operations at the top molds. the welding voperations take place at the adjacent side molds. y

Each mold is made up of three parts comprising the shells 41, the ejectors 48 and the bottoms 49, all machined to easy sliding fits lwithin the other in the order named. The exterior surfaces of `the shells are machined to easy slldingyflts in the carrier housings 50 whichv are integral with the carrier castings. The three members namedg() form the matrices--the shells forming theedges of the half blocks. In the construction showntlie. shells 41 and the bottoms 49 are at all.,A e rigidly connected together, the ejector 48 sliding fk5 between them. f7 In the pressing operation the moldparts' are all within their housings, as shown at the top mold in Fig. 4. At theA next stage, shown at the leftin Fig. 4, the sliding mold members in mary pneumatic means, hereinafter described,

until the mold'shells are in contact, in which operation the welding takes place. After a very short interval of time the shells are drawn inwardly by the reversal of this pneumatic force. At this part of the cycle, however, the ejectors 49 are held by a secondary pneumatic means in contact with the now welded block, the edges of which are exposed by the recession' of the shells, as shown clearly in Fig. 5. At this juncture the shells have not quite reached the limit of their receding travel andthe glass block is still held by the eiectors. Upon further recession, that ls to say to their limits, the bottom members 49 75 mold carriers have been forced outwar d1 y by mi pawls engage the ratchet blocks |09, thus holdl -eiectedblockl In returning to their normal posil impact with the inwardly extending anges of the ejectors 48 causing them also to recede a suillcient -amount to release the formed and Welded block which then falls by gravity to conveying means. In the latter operation it is understood that the primary pneumatic means, being. much the stronger, overcome the secondary means, both being active at this time. Y

In detailed description of the pneumatic means above referred to, the timing valve V-Z, is similar in construction and operation. to the plunger timer V-l, shown in Fig. 8, and the cam T--Z 'is similar to the timer rI4`I and on the same shaft. At the `beginning of the welding cycle air pressure is admitted through the pipe 5I to the automatic hold-down cylinder 52 'from whence it is communicated through the pipes 52-ato the primary'cylinders C-I, forcing the pistons P-I outwardly and `with them the mold parts 41 48, 49.

Upon a further-rotation of the timer cam T-2, the valve V-Z is reversed and air pressure is admitted through the automatic hold-down cylinder 53 and the pipes 53--a to thestulng box ends of the primary cylinders Cl, thereby returning the pistons P-I to their normal positions. It will be noted that the compressed air ducts 53-a lead` positions. due to their gravity.

- Referring to Fig. 14, it is obvious that the outwardly moving piston P -I will compi-ess thefconfined air-ln.r the pair of cylinders 6 2. These latter cylinders thus actas dash-pots for cushioning the-outward travel of. the mold parts, the cushioning effect being adjusted by opening or closing the relief cocks'shown at the tops of the radius is half way rbetween its maximum and minimum radii, the valve portsbeing then closed.

. In Fig. 3 there is'shown an alternate-method of holding theeiectors 4 8 in contact with the block during the recession of the other mold members.

pin members III and the springs H2'. When the mold parts are rforced outwardly the release pins 1 are carried by the disks H3 along with the mold moving members.' This releases the pawls lili so that at the-end of the outward movement .thetv .ing them and the ejectors 48 in contact with the y",

tions the shells 47, near the ends of their receding travel, depress the release pins lll disengaging the ratchets as shown in Fig. 3. The springs H2 are under compression between the mold housings and the threadedanged nuts H3 which are shown as threaded upon extensions from the ratchet blocks 109, thus providing spring tension adjustment. The purpose of-q these springs is to return the ejectors to their normal positions when the ratchets are releasedn The function and effect of the two described methods of holding and releasing the ejected I pieces of rubber hose, not shown.

blocks are identical and either may be substituted for the other.

Referring to Fig. 3, it is observed that the sliding mold members 41, 48, 49 may be disassembled from their housings by first removing the connecting pins 54, and the water outlet pipes 65, 86 and loosening the unions HM, H5.

In the final event of the welding cycle the timer cams T-2 return the valve pistons to their original position or mid-stroke, represented by the cylindrical surface of the cams which have a radius half Way between their highest and lowest contacting surfaces, theyalve inlet p'orts being then closed.

In order that the compressed air from the xed external piping may be conducted Yto the quadrivlal piping systems within the rotative lmold carriers the plane machined surface of the disk 58 is held bythe spring 59 under. light pressure against a similar surface on the adjacent side of the Geneva gear wheels 22. During the dwell periods of the mold carriers the two ports in the disk 58 are in register with two correspondy ing ports, set in radial linesl in the Genevagear hub as in Figures 1 and 3. To provide against leakage fromthe contacting surfaces of the disk and gear hubs the hold-down air cylinders 52, 53 are made integral parts of the disks and are fitted the cup leather pistons whose stems bear against.` the fixed standards 80. It will be seen that when the air pressure enters either of the pairs of cylinders, the area of the pistons being much greater than the area of the outlet ports, the disks will be held with strong pressure against the wheel hubs due to the reaction of the piston stems against the fixed supports 60. l

The inner hubs of the Geneva gear wheels are in air-tight contact with the ends of the mold carrier hubs and in register through both of these members are the ductsxBIf-SZ, four of each pair, positionedY quadrantally, and each pair successively in register with the outlets" from the cylinders 52, 53, as shownin dotted lines 4in Fig. 1. Pipes 63, 64 are led from each of the four pairs of ducts to the primary and secondary air cylinders C-I and C-2 and connecting therewith in the manner above described. t t f For the purpose of coolinggthe molds, their bottom members 49 are. made-hollow sothat the cooling medium, entering their tubular stems 49-b, divides laterally and discharges ing equal volumes through the pipes 85, 86 into the overflow collecting rings 81; 88.56 shape in section as shown in Fig. 3, from whence\ it flows through Waste pipes.

The water, or

swivel joints 69 andthe axial ducts 10 to the junctions ofthe four radial branch ducts leading through the pipes 1I to nozzles on the outside of the mold carrier hubs from whence it is conducted to the mold inlets 12 through short The meansfor receiving'each finished block t and for lowering it to a level in which it clears ,the molds during the succeeding indexing 'period of the moldcarriers without excessive drop by gravity comprises the vertically reciprocating plate 96, `Figures 1 2, 13, the chute 91 and timed means for actuating the plate with relation to the mold carrier cycles.v

other cooling medium passes from an external source through the rotaryproduced in the half blocks by the ilow of thel by the hereinbefore described machine.' The,

In order that each block may be removed from the plate in timed relation to the movement of Y the mold carriers the chute is set at an angle of inclination which causes the block to slide thereon by gravity when the plate is lowered.

A rectangular section is cut from the bottom yof the chute to permit the passage of the plate -the plate and ,chute opening are less than the thickness of the block, as shown in Fig. 13. At the bottom of the chute the block is carried away by any well known type of conveyor, such as the belt conveyor 98. The sprocket 99 is keyed on an extension of one of the intermediate shafts |1 and a similar sprocket, with one to one ratio, is keyed on the take-out .shaft |0I, these sprockets being geared together by the chain |02'. The crank |03 has the roller |04 which moves within the closed cam, |05, which is guidedby rods |01 through guides |06 thus imparting vertical reciprocating motion to the cam and to the connected plateSB in synchroxnism with the movements of themold carrier andpther reciprocating members. The concaved section on the Working surface of the upper half of the cam, |05-a, causes it and the plate to remain stationary during the short interval of time during which the nished block is deposited upon it.

It is well known that articles of hot glass in the plastic state will firmly cohere when brought together' thus producing practically perfect welds. As the half blocks are entirely within the molds when brought together the seams at their plane of junctibn will show but slightly in the iinished product with accurate coalignment of the molds.

In building the walls, the blocks may be. laid with broken joints in the manner of ordinary clay tions P, Figures 16 to 21, inclusive, are provided. i, n

In Figures 16 to 21, inclusive, these partitions are molten glass under pressure into the notches 31-a in the bottoms of the plungers as in Fig. 6.- Evidently three or even more of such partitions may be thus formed when the blocks are required to resist extraordinary compression in the walls.

In molding blocks which have Very thin'walls it may be advantageous to prevent the forming of partial vacuums in their interior cells. In this case and for this-purpose the mold caps 40 have at both ends the small downwardly extending prisms 40-a which leave small notches in the rims of the half blocks at this point. These notches coincide in the halves and, after welding,

leave small vents through which air may pass thus preventing the formation of vacuums.

In the prevailing custom the exposed surfaces of the blocks, and often the interior-surfaces as well, have a multiplicity of small ridges or sinuous corrugations formedthereon. It is obvious that the mold bottoms or plunger bottoms, or both, in the above described members may be machined so as to form these` corrugations.

In Figures 16 to 22, inclusive, are shown some of the glass blocks nowA commonly used as made small protuberances |20, Figures 17 and 19, are caused by the excess amount of glass in the beveled rim edges |2| of the block halves to be weldedfas shown in Figs. 16 to 18. With' properly designed mold caps the welded joints should be scarcely discernible. p

In the block shown in Fig. 19. the halves Fig. 18,

are similar in every respect Iwhile in those shown in Fig. 17, the halves, Fig. 16, are dissimilar, one including the outer wall surface and the other the irrier wall surface and ends.

For making blocks having curved wall surfaces of very long or very short radii, the manner shown in Fig. 16 would be diiilcult or impracticable. To overcome this diiliculty these curved blocks, or others of any desired design, are made as shown in halves in Fig. 21 and in section in Fig. 20 or 22. By this method the molds and half blocks are alike for every design, the Welded joint being in a plane midway between the plane surfaces and parallel thereto. In this case the curved walls are formed by the mold shells, each having a slight draft for freeing the halves. I'he welding in this manner of marketable blocks at anon-prohibitive cost is practicable by the hereinbefore described method of autogenous welding and by no other method.

I claim:

1. In a pressing and welding machine for making hollow glass blocks which are mounted two machines in co-active relation, one to Ythe other, and comprising auto-l matically actuated and synchronized mold carry ing members mounted upon horizontal axes and rotated in progressively intermittent turns, sliding mold members mounted 90 .apart around each of said carrying members, and positioned so that one mold in each carrier at the top of the carrier and the same two molds are moved by the next step of the carriers to the adjacent sides of the carriers. means for adjusting the angular position of the two carriers and for locking them in working positions during the pressing, welding and ejecting operations with the adjacent molds of the two carriers in alignment. Y

2. In a pressing and welding machine for making hollow glass blocks comprising a pair of co acting mold carriers, means for intermittently rotating said carriers upon horizontal axes in quarter turns, housings in said carriers in quadrantal circumferential spacing Within which are slidably contained mold shells, mold bottoms and ejectors, adapted to mold a half block, and means for actuating the slidable members in adjacent housings in the two carriers during the period of rest to protrude all said members simultaneously until the half blocks carried thereby contact and are welded, and then to retract the mold shells and bottoms, leaving the welded block supported by the ejectors, and iinally to withdraw the ejectors and discharge'the block.

3. In a pressing and welding machine for making hollow glass blocks a pair of co-acting mold carriers, means to rotate the carriers intermittently in quarter-turns and successive rest periods, quadrantally disposed housingsin said carriers having thereinslidable mold members comprisinar outer shells and inner mold bottoms which are bound together, ejectos mounted to slide within certain limits between the said outer shells and mold bottoms, synchronized pneumatic means for protruding the said sliding members as a unit, ratchet and pawl means for holding the ejectors in their protruded positions during the recession of the said shell and bottom mem-bers and pins for releasing the pawls from the ratchets at the end of the recessicn of the shell and bottom members which at that time depress the said pins for the purpose stated.

a common base upon quarter 4. In a pressingand welding machine for making/hollow glass blocks the combination of a nonrotative disk having a pair of ports which register thereof, means with similar ports in radial lines Ain an intermittently rotating member during the period between intermittent movements of said member, said disk being in close contact with the rotative member and held thereagainst by a spring, a pair of cylinders having inlets connected to pipes from a pneumatic timing valve and outlets through the ports in rthe disk, pistons within said cylinders having stems which contact 4with and react against a xed.member thereby causing extra pressure of the disk against the said rotative member during the said periods of time, as controlled by the timing valve.

5. Apparatus for forming blocks comprising two molds, each having an open side, means to form a half block in each mold fromplastic glass, means to position the molds with their open sides towards each other, means to project the molds rectilinearly towards each other until the half blocks therein contact and weld together, and means to withdraw the molds rectilinearly from the welded block.

' 6. Apparatus for forming hollow blocks com; prising two mold carriers mounted upon parallel.

horizontal axes, a multiplicity of molds mounted on each carrier and facing outward on the periphery thereof, means for moving the two carriers intermittently and synchronously,l means for stopping each movement of the carriers with the molds on` the adjacent sides of the carriers in alignment therewith, means for molding ahalf block -fromplastic glass in each mold -before it reaches said position of alignment with the mold on the other carrier, means to move the two molds rectilinearly in said position of alignment towards each other until the half blocks Itherein are brought in contact, whereby said half blocks are welded to complete a block, and means for Aejecting` the finished blocks from the molds and for depositing the blocks upon ya conveyor.

7. Apparatus for forming blocks comprising two molds,l each having an open side, means to form a half block in each mold from plastic glass, means to position the molds with their open sides towards each other, means to project the molds in said position. until the half blocks therein` contact and weld together, means to withdraw the molds from the welded block, a block support movable vertically beneath the position of the welded block, and means to raise and lower said support in timed relation with the movement of the molds to position it in its upper position when the molds are moved apart and thereafter lower it with the block thereon.

8'., Apparatus for forming hollow blocks comprising two mold carriers mounted upon parallel horizontal axes, a series of molds mounted on each carrier and facing outward yon the periphery for moving the two carriers intermittently and synchronously, means for stopping each movement of the carriers with the molds on the adjacent sides of the carriers in in said-position of alignment towards each other until the half blocks therein are brought in contact, whereby said half lblocks are welded to com plete a block, and means for separating the two mold shells after the .block halves are welded position in which it is' means for bringing AWhile they are in glass and sliding `said plungers and 'tacting the rim edges of the half blocks projec- ,half block registering from contact with the block.

9. Apparatus for forming hollow blocks comprising two mold carriers mounted upon parallel horizontal axes, a series of molds mounted on each carrier and facing outward on the periphery thereof, means for moving the two carriers intermittently and synchronously, means for stopping each movement of the carriers with the molds on the adjacent sides of the carriers in; means for molding alignment with each other, a half block from plastic glass in'each mold before it reaches said position of alignment with the mold on the other carrier, each mold comprising a mold' shell, a mold bottom, and an ejector surrounding the mold bottom within the mold shell, means to move the two molds in said position of alignment towards each other until the half blocks thereinV are brought in Contact, whereby said half -blocks are welded to complete the block, and means for projecting the mold shell and bottom together and separately operating the ejector.

10. Apparatus for forming hollow blocks comprising two adjacent rotary mold carriers, a multiplicity of equally spaced outwardly open molds on each carrier, means for rotating the carriers intermittently and synchronously in opposite directions, rectilinearly reciprocating into contact and receding the molds in the twol carriers while they are in adjacent, welding, positions, `plunger means for forming the half blocks at 90 spacing from their welding positions, and means for 'electing the welded blocks and for delivering them to a conveyor.

l1.- Apparatus for forming hollow glass blocks comprising two adjacent rotary mold carriers, a multiplicity of equally spaced outwardly opening molds in each carrier, means for rotating the two carriers intermittently and synchronously, rectilinearly reciprocating means for bringing into contact and receding the molds in the carriers while they are in adjacent positions for welding the glass, plungers for forming half blocks in two molds, one mold on each carrier simultaneously their pressing position, and mold caps having beveled surfaces contacting the on said plungers for shaping the beveled rim edges so that their inner sides extend farther from sides which are flush with the molds.

12. In an apparatus glass blocks comprising two adjacent mold carriers each with a multiplicity of molds, plungersfor forming glass block halves, mold caps sliding upon having on their surfaces contions to form notches therein, the notches in each during welding so as to form a vent in the block wall, means for projecting the two adjacent molds rectilinearly towards each other until the half blocks therein contained contact and weld together, and means to cause rectilinear recession of the welding molds and to release the finished blocks.

13. Apparatus for comprising two adjacent mold carriers mounted for forming and welding together and thereafter withdrawing the ejectors A side by side upon parallel axes, a multiplicity of molds in each carrier opening outwardly on the vperiphery of the carrier, each mold comprising a shell sliding the molds than their outer v forming hollow glass blocks within a socket in the carrier and adapted to surround the closed sides of a half block formed in the mold, synchronized means for sliding adjacent mold shellsof the two carriers together to weld a pair of half blocks together, a separately operated ejector within veach shell and adapted to contact the closed side of each half block in the position in which it was originally formed, synchronized means for separating the mold shells after the block halves are welded together and thereafter withdrawing the ejectors from contact with and thus releasing the welded block, synchronizedplunger means for forming the half blocks in the top molds of each carrier, and means for rotating the two carriers intermittently and synchronously. l

14. Apparatus for forming and welding glass blocks comprising two adjacent carriers rotatable about horizontal axes each with a multiplicity of radially sliding mold parts, means for forming a half block in the top mold of each carrier, means for welding the half blocks formed in one carrier to those formed in the adjacent carrier and for ejecting the finished blocks, the forming means including plunger and sliding cap means, the cap means having beveled -edges for forming beveled edges on the block rims. thus providing surplus material on the inside of said rims, and intermittent synchronized means for operating the forming and welding mechanisms and for rotating the carriers.

15. Apparatus for forming and welding glass blocks comprising two adjacent carriers rotatable about horizontal axes each with a multiplicitypf radially sliding mold parts, means for forming a half block in the top mold of each carrier, means for welding the half blocks formed in one carrier to those formed in the adjacent carrier andfor ejecting the finished blocks, the forming means including plunger and sliding cap means, the cap means having downward projecting parts for forming notches in the half block rims, said notches registering during the welding thus forming a vent in a wall of the finished block and synchronized means' for intermittently operating the forming andwelding mechanisms and for rotating the carriers.

16. The method of ma ng hollow glass blocks comprising molding from hot plastic glass two similar block halves, each in a sourrounding mold with an open side and each forming a box-like body with an open side at the open side of the mold and with the wall of the box projecting from the mold at its inner face while its outer face is flush with the mold, thus forming beveled edges, and subsequently bringing the open sides of the molds together in rectilinear motion, and forcing said beveled edges together While they are at welding temperature thereby welding the half blocl'` i together, and causing a surplus of glass to `be extruded inwardly thereby forming a bead 

